Improvement in metallic tubing



0. G. SMITH. METALLIC TUBING.

N0. 107.731 Patented Sept. 27, 1870.

M212 1 5? 1 02% 'J I I VnwWM ifgywLz tinned $131M e can.

CHARLES e. SMI H, OF CHELSEA, ASSIGNOR T0 AMERICAN METALLIC TUBING COMPANY. or BOSTON, MASSACHUSETTS.

IMPROVEMENT IN .METALLIC TUBING.

The Schedul referred to in these Letters Patent and making part of the same To all whom it may concern Be it known that LCHAnLEsG. snnzrn, of (Jhcl sea, in the county of Suii'olk and State of Massachusfetts, have invented an Improvement in Metallic Tubing; and I do hereby declare that the following, taken in connection with the drawing which accompanies and formspart of this specification, is a description of my inventiou s'uificient to-enable those skilled in the art to practice it.

-United States Letters Patent No. 57,783, dated September 4, 1866, were granted to me for an improvement in the manufacture of lap-seamed metal tubing, the invention consisting in an organization of mechanism by which a long plate, of proper can. to form the tube, is gradually and progressively bent by a serics-ofirolls' around the surface of a cylindrical mandrel, the opposite edges being brought together and folded and pressed down upon the tube, so as to form a tight or compact lap-joint.

In the tubes made by the specific organization described in such patent, no provision existed for looking the lapped edges together, other than their simple tight Contact, and in twisting the tubes with a sort of wringing motion, the lapped edges will slip.

' The object of my present invent-ion is to so construct the tube that relative slipping of the parts is impossible, and this I accomplish by making, in the outer face of the seam, a series of indentations, the spurs formcdou the opposite sides of which are forced, into themetai of the adjacent plate, thus locking the two joint-forming edges together, and preventing relative displacement.

My invention consists in a tubethus made.

Thedrawiug represents a piece of tubing embodying the improvement.

A showsa plan, and

B',a cross-section of the tube.

n denotes thebody of the tube.

b c, the lapped and folded edges.

In the outermost edge or surface of the joint I strike, with a punch-point or other suitable device, 7

the indentations d, in such manner as to displace and interlock the mctaiof the adjacent joint-forming layers, as seen at 'B. 7

It, will be obvious that, when thus treated, thcjoint is strengthened, and the edges so held that they cannot slip endwis e, the spurs having substantially the same efiect as rivets; A

,In' the manufacture of the improved tubing, I prefer to use the process covered by my patent abovere- 'ferred to, placing on the perimeter of the finishing roll that flattens down the scam the spurs or points that form the indentations, so that the tube 'comcs fromt-he machine in finished condition, as shown in the drawing.

I claim--- As a new article of manufiicturc, lap-jointed metal tubing, having the joint-forming edges locked together by spurs or projections, substantially as shown and described.

Signed August 18, 1870. v

CHARLES G. SMITH.

Witnesses:

FRANCIS GOULD, S. G. REED. 

